How do you measure for compression socks?

Compression socks are sized by the circumference of your leg, not by your shoe size. This is the single most common mistake, and it is why so many people conclude compression socks do not work for them.

A sock sized to the wrong leg measurement does not deliver graduated compression at all. Too small and it becomes a tourniquet at the calf. Too large and it does nothing.

Measure in the morning

Before you have been on your feet. Your legs swell through the day, sometimes considerably — measuring in the evening gives you a number that will be too big by morning, and a sock that is loose exactly when you need it working.

Take the measurements sitting down, feet flat on the floor.

Knee-high socks: two measurements

Ankle. The narrowest point, just above the ankle bone. This is the most important number — it is where the compression rating is defined.

Calf. The widest point of your calf muscle.

Some charts also ask for the length from the floor to the bend of your knee.

Thigh-high: three measurements

Ankle and calf as above, plus the widest part of your thigh. All three need to be in range. A thigh-high that fits at the calf but is tight at the thigh creates a constricting band at the top — the opposite of graduated compression, and genuinely counterproductive.

Wide calf

If your calf measurement falls outside a brand's standard range, buy a wide-calf sock rather than sizing up the whole sock. Sizing up gives you a loose ankle — and a loose ankle means no graduated compression, because that is where the gradient starts.

Wide-calf socks are knitted wider from the start, so the gradient holds across a larger leg. Many go to 5XL or 6XL.

Between two sizes?

For compression socks specifically, go up. A sock slightly too large still provides compression. A sock too small can restrict circulation, and it will be a fight to get on every morning.

How to know the fit is right

It should feel firm at the ankle, noticeably lighter at the top, and even in between. There should be no band of tightness anywhere, no deep marks when you remove it, and no numbness, tingling or colour change in your toes.

If you get any of those, take it off and check your measurements again.